The present invention relates to a servo transfer feeder that is used for a press line, and a method for controlling a servo transfer feeder.
A transfer press line includes a plurality of presses that are provided with an upper die and a lower die, and a transfer feeder that transfers the workpiece from the upstream press to the downstream press. The transfer press line can achieve high productivity and save space by successively performing a plurality of press steps (e.g., punching, bending, and drawing).
A servo transfer feeder has been increasingly used as the transfer feeder included in the transfer press line instead of a mechanical transfer feeder. The servo transfer feeder contributes to an improvement in performance of the press line since various transfer motions can be easily set and changed.
For example, the moving distance of the lift motion of the servo transfer feeder can be set corresponding to the workpiece to have a minimum value at which interference of the workpiece with the lower die can be prevented. When implementing shallow drawing, the workpiece can be transferred at high speed by reducing the moving distance of the lift motion of the servo transfer feeder. When implementing deep drawing, a product provided with a high degree of drawing can be lifted, and the workpiece can be transferred at a stable speed by increasing the moving distance of the lift motion of the servo transfer feeder. When the height at which the workpiece is placed on the die differs between the upstream press and the downstream press, the workpiece can be transferred at an optimum height by appropriately adjusting the workpiece hold/release position of the servo transfer feeder. According to the servo transfer feeder, the production efficiency of the transfer press line can be improved by appropriately selecting a transfer motion optimum for the press conditions of the transfer press line.
It is important to appropriately set a transfer motion optimum for the press conditions.
For example, JP-A-2004-255417 (“Feeder teaching motion setting method”) discloses a method that sets the positions of twelve teaching points to generate a transfer motion. According to the transfer motion generation method disclosed in JP-A-2004-255417, since the speed of synthesis between the adjacent teaching points can be easily set within the possible range, the number of operations for setting the transfer motion can be reduced, and operability can be improved.
JP-A-2011-131290 (“Transfer path setting method”) discloses a method that automatically sets the workpiece transfer path corresponding to the shape of the die. According to the transfer motion generation method disclosed in JP-A-2011-131290, the calculation time required to set the transfer path can be significantly reduced by automatically calculating the transfer path using CAD data based on lower die/upper die shape data.
Since the transfer path setting method disclosed in JP-A-2011-131290 automatically calculates the transfer path using CAD data based on lower die/upper die shape data, it is possible to prevent unstable transfer that may occur when using the method disclosed in JP-A-2004-255417.
JP-A-5-90386 (“Transfer device”) discloses a method that reduces vibrations and impact applied to the transfer target object by driving a motor according to a cam curve when transferring the transfer target object by driving a direct drive motor.